Intraabdominal leg: unique variant of split notochord syndrome.

An infant was born with a spectrum of anomalies representing a unique variant of the split notochord syndrome. The major anomalies included giant omphalocele and duplicated lower spine, between which developed a posterior lumbosacral mass that was contiguous with an intraabdominal, skin-covered "leg" within a saccular cecum. Features of this case overlap aspects of fetiform teratoma, fetus-in-fetu, conjoined twins, and caudal duplication, suggesting an etiologic relation between these entities and split notochord syndrome.